Reed contact arranged within a protective envelope



R. SCHEIDIG Feb. 16, 1965 REED CONTACT ARRANGED WITHIN A PROTECTIVEENVELOPE Original Filed NOV. 18, 1959 INVENTOR. R.SCHEIDIG Agent l'*-A... n. i

United States Patent 3,170,053 REED CQNTACTARRANGED WKTHIN A PROTECTIVEENVELGPE Rudolf Scheidig, Stuttgart-Feuerbach, Germany, assignor toInternational Standard Electric Corporation, New York, N.Y., acorporation oi Delaware Continuation of application Ser. No. 853,774,Nov. 18, 1959. This application Oct. 1, 1963, Ser. No. 313,043 Claimspriority, application Germany, Dec. 6, 195$, fit 14,534 2 Claims. (Cl.200-87) This application is a continuation of my copending applicationSerial No. 853,774, filed November 18, 1959, and entitled Reed ContactArranged Within a Protective Envelope, now abandoned.

The present invention relates to a reed contact arranged within aprotective envelope, and which is capable of being actuated by amagnetic field, as is already known per se.

In one conventional type of embodiment which has the advantage overother conventional types of reed contacts having a very short overalllength, the conductors provided for establishing the connection with thereed contact, are arranged at one and the same end of the protectiveenvelope. The stationary contact part is short, and the moving contactpart is a long bifurcated form for providing a sufiicient resiliency.

This prior art construction, however, has a disadvantage. A compressionof the magnetic field in the airgap between the two contact parts isnecessary to move producing the force required for the contact. But thiscompression can only be produced if the limb of the bifurcated contactpart, forming a magnetic shunt therewith, has a resistance value whichis comparable with the resistance of the airgap. This resistance valueoccurs when the contact part has a high saturation. This construction,however, requires a very high magnetomotive force.

It is now the object of the present invention to eliminate this drawbackand, by maintaining the small overall length, to achieve a sufficientcontact-making force with an unobjectionably reliable function, and yetrequiring a small as possible magnetomotive force. According to theinvention this is accomplished in that the moving part of the reedcontact consisting of a ferromagnetic material, with the aid of astationary part not consisting of a ferromagnetic material, is securedto a connecting conductor, whereby both parts of the reed contactpreferably have the same or almost the same rigidity (inflexibility).

In further embodying the construction of the reed contact according tothe invention, it is possible to provide a switch-oft contact, bydesigning the contact in such a way that the moving part of the reedcontact is provided with a portion of a non-ferromagnetic materialconductively touching the connecting conductor which is not connectedwith the moving part of the reed contact, by way of an elastic bias,thus forming a switch-off contact.

According to a further modification of this type of embodiment it ispossible to construct a switchover contact by inserting between themoving part of the reed contact and the connecting conductor which is ina conductive connection therewith via the non-moving (stationary) partofthe reed contact, a further connecting conductor in such a way that bythe conductive touch or contact of this conductor with the moving partof the reed contact by separating the contact of the part from theconnecting conductor which is not in a fixed conductive connection InFIGS. l-3 of the accompanying drawing there are "ice shown some examplesof embodiment of the contact according to the invention:

In FIG. 1 there is shown a switch-on contact,

In FIG. 2 there is shown a switch-off contact, and

In FIG. 3 there is shown a switch-over contact.

The connecting conductors 1, 2, 8 of a ferromagnetic material areinserted at one and the same end 3 of the protective envelope 4 which,in the manner known per se, may either be filled with a protective gas,or may be evacuated of air. The moving part 5 of the reed contact, in alikewise conventional manner, consists of a ferromagnetic material. Thismaterial may either be of the ferromagnetically soft kind or, forachieving any probably wanted remanence effects, may also be oftheferromagnetically hard kind.

The electrically conductive connection between the connecting conductor2 and themoving part 5 of the reed contact is established by a part 6 ofthe reed contact consisting of a non-ferromagnetic material, preferablyhaving the same elastic rigidity as the moving part 5 of the reedcontact. In FIGS. 1-3 the parts consisting of the non-ferromagneticmaterial are indicated by the shaded portions. The moving part 5 of thereed cont-act consisting of a ferromagnetic material is arranged in sucha Way that the contact opening is arranged on the side of the connectingconductor 1 not facing the connecting condoctor 2, because on account ofthis the lines of stray flux extending from the connecting conductor 2to the contact part 5 are capable of being utilized as well foractuating the contact.

The switch-cit contact as shown in FIG. 2 is provided with a moving part5 of the reed contact consisting of a ferromagnetic material, carrying apart 7' consisting of a non-ferromagnetic material. This part 7 isadapted to establish the conductive connection between the connectingconductor 2 .and the connecting conductor 1 in that it is pressed by thepart 5, with the aid of an elastic or flexible bias, which is indicatedby the arrow 9, against the connecting conductor 1.

Under the influence of a magnetic field the moving part 5 of the reedcontact is moved towards the connecting conductor 2, thereby separatingthe part 7 from the connecting conductor 1, so that the switch-01fcontact will be opened.

FIG. 3 finally, shows a combination of a switch-on contact according toFIG. 1 with a switch-off contact according to FIG. 2, for forming aswitch-over contact. The three connecting conductors 1, 2, 8 are againattached to the same end 3 of the protective envelope 4. The function ofthe switch-over contact will be easily understood from the descriptionof the switch-on'and switch-off con 7 tact given hereinbefore withreference to FIG. 3.

While I have described above the'principles of my invention in conectionwith specific apparatus, it is to be clearly understood that thisdescription is made only by way of example and not as a limitation tothe scope of my invention as set forth in the objects thereof and in theaccompanying claims.

I claim:

1. A reed contact assembly for controlling the continuity of at leastone electrical circuit responsive to externally applied magnetic fieldscomprising a stationary contact of magnetic material and a movablecontact sealed in a tube, said movable contact including a first bladeof non-magnetic material and a second blade of magnetic material, saidfirst and second blades being joined at one end to form a resilientbifurcated structure, means comprising the tip of the other end of saidfirst blade for providing an electrical circuit through the wall of saidtube and a fixed end mount for said resilient structure, the other endof said resilient structure being free to move, the

tip of the other end of said second blade being positioned adjacent saidstationary contact, whereby substantially all of the flux in saidmagnetic field is compressed in the air gap between said stationarycontact and said second blade and substantially none of said flux isshunted through said first blade, an elongated contact member attachedto and supported by the other end of said second blade, said elongatedcontact member extending away from said blade at a substantially largeangle approximating 90" with respect to the length of said bifurcatedstructure, said elongated contact member making or breaking anelectrical circuit through said stationary contact depending uponWhether said reed contact is normal or is operated, the other end ofsaid second blade being positioned near a terminal leading through saidWall, said elongated contact extension having a first portion positionedadjacent said stationary contact for movement into and out of electricalcontact with the stationary contact and another portion movable into andout of electrical contact with said terminal.

2. A magnetically operated reed-contact assembly ac- 41 cording to claim1 wherein the said other end of said second blade makes electricalcontact with the said terminal concurrently with a breaking of theelectrical contact with the stationary contact.

Retereuces Cited by the Examiner UNITED STATES PATENTS 2,029,266 1/36Leece et al. 200-87 2,587,551 2/52 Van Riper 200-113 2,759,064 8/56Walley 200-122 2,785,249 3/57 Meyer 20087 2,892,051 6/59 Moore 200-812,922,856 1/60 Karrer 200-87 2,969,434 1/ 61 McGuire et al. 200-873,014,102 12/61 Dalbianco et al. ZOO-87 FOREIGN PATENTS 612,952 11/48Great Britain.

20 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

1. A REED CONTACT ASSEMBLY FOR CONTROLLING THE CONTINUITY OF AT LEASTONE ELECTRICAL CIRCUIT RESPONSIVE TO EXTERNALLY APPLIED MAGNETIC FIELDSCOMPRISING A STATIONARY CONTACT OF MAGNETIC MATERIAL AND A MOVABLECONTACT SEALED IN A TUBE, SAID MOVABLE CONTACT INCLUDING A FIRST BLADEOF NON-MAGNETIC MATERIAL AND A SECOND BLADE OF MAGNETIC MATERIAL, SAIDFIRST AND SECOND BLADES BEING JOINED AT ONE END TO FORM A RESILIENTBIFURCATED STRUCTURE, MEANS COMPRISING THE TIP OF THE OTHER END OF SAIDFIRST BLADE FOR PROVIDING AN ELECTRICAL CIRCUIT THROUGH THE WALL OF SAIDTUBE AND A FIXED END MOUNT FOR SAID RESILIENT STRUCTURE, THE OTHER ENDOF SAID RESILIENT STRUCTURE BEING FREE TO MOVE, THE TIP OF THE OTHER ENDOF SAID SECOND BLADE BEING POSITIONED ADJACENT SAID STATIONARY CONTACT,WHEREBY SUBSTANTIALLY ALL OF THE FLUX IN SAID MAGNETIC FIELD ISCOMPRESSED IN THE AIR GAP BETWEEN SAID STATIONARY CONTACT AND SAIDSECOND BLADE AND SUBSTANTIALLY NONE OF SAID FLUX IS SHUNTED THROUGH SAIDFIRST BLADE, AN ELONGATED CONTACT MEMBER ATTACHED TO AND SUPPORTED BYTHE OTHER END OF SAID SECOND BLADE, SAID ELONGATED CONTACT MEMBEREXTENDING AWAY FROM SAID BLADE AT A SUBSTANTIALLY LARGE ANGLEAPPROXIMATING 90* WITH RESPECT TO THE LENGTH OF SAID BIFURCATEDSTRUCTURE, SAID ELONGATED CONTACT MEMBER MAKING OR BREAKING ANELECTRICAL CIRCUIT THROUGH SAID STATIONARY CONTACT DEPENDING UPONWHETHER SAID REED CONTACT IS NORMAL OR IS OPERATED, THE OTHER END OFSAID SECOND BLADE BEING POSITIONED NEAR A TERMINAL LEADING THROUGH SAIDWALL, SAID ELONGATED CONTACT EXTENSION HAVING A FIRST PORTION POSITIONEDADJACENT SAID STATIONARY CONTACT FOR MOVEMENT INTO AND OUT OF ELECTRICALCONTACT WITH THE STATIONARY CONTACT AND ANOTHER PORTION MOVABLE INTO ANDOUT OF ELECTRICAL CONTACT WITH SAID TERMINAL.